Introduction to Ecology

Introduction to Ecology

• Ecology is the study of relationships between living organisms and their environment.
• Humans are an integral part of ecological systems and depend on them for survival and quality of life.
• The human population is rapidly increasing and altering the biosphere, potentially jeopardizing human civilization's sustainability.
• The human population reached 7.888 billion in 2021 and is projected to reach 8.3 billion in 2024.
• The doubling time of the human population is roughly 61 years.

What is Ecology?

• Ecology is the study of how living organisms interact with their environments.
• Ecology, coined by Ernest Haeckel in 1866, originates from the Greek word "oikos", meaning "home" or "place of dwelling".

Why care about ecology?

• Humans depend on ecological systems for survival and quality of life.
• Human activities significantly alter the biosphere, reducing it's capacity to support future civilizations.

Trajectory of the human population

• The human population has experienced exponential growth since the beginning of the common era.
• Graph depicting the exponential growth of the human population from 1AD to 2000AD (as understood in 1970).

Eswatini Population

• Population density map of Eswatini showing variations in population distribution.
• Line graph depicting the population growth trend of Eswatini from 1950 to 2024.

Earth at night & USA at night

• Images depict global and national (USA) levels of human activity at night. Illustrated using light intensity.

Humans & the Biosphere

• Global human population: 7.888 billion in 2021 (approaching 8.3 billion in 2024).
• Doubling time of the human population is approximately 61 years.
• The rapid increase in human population and its impact on the biosphere is a significant concern.

The Blue Planet

• Earth is the only known planet with life.
• The biosphere is fragile and humans depend on it for all their needs and wants.
• Ecology is the understanding of the living organisms and the interaction with the physical environment.

Global Atmospheric Changes

• Ozone depletion and global warming are evident concerns related to human activity and waste products.

Global Warming

• Historical evidence of global warming, including changes in summer Arctic sea ice boundary (1979 images, 2004 images comparative analysis).
• Alpine glacier retreats (1875 to 2004 images).
• Global warming is happening at an accelerating rate.

Homo sapiens as a species

• The relationship between humanity and nature is complex.
• Questions arise about whether humans are “natural” and whether they are subject to ecological principles.
• Humans display unprecedented effect on the biosphere.

What is Ecology?

• Ecology is the scientific field that describes and explains the relationships between organisms and their environment.
• Ecologists study and quantify organism-environment interactions.

Another definition of ecology

• Ecology's goal is to understand patterns in organism distribution and abundance.
• Ecologists develop and test hypotheses to explain these distributions.

In summary ecology is...

• The investigation of living organisms in their natural surroundings.
• How organisms interact with each other.
• How organisms interact with their non-living environment.

What do we mean by the environment?

• An organism's environment comprises all external factors and phenomena influencing it.
• Biotic factors are living organisms.
• Abiotic factors are non-living components (like temperature, soil, light, moisture, air currents).

Ecosystem

• Ecosystems encompass all organisms and nonliving components in a defined area.
• Abiotic factors influence all living organisms in the ecosystem.
• Interactions within an ecosystem are crucial for survival.

What do we mean by interactions?

• Interactions happen between organisms and their environment.
• Ecosystem components interact for survival.

Levels of Organization

• The study of environmental systems includes the understanding of various levels of interacting systems from atoms to the universe.

Levels of Organization (Part 2)

• Ecologists investigate organisms at several levels, from individuals to the biosphere. 

Organisms

• An organism is a single living being, such as a crocodile.

Population

• A population is a group of the same species living in a specific area.
• Population growth or decline is influenced by births and deaths.

Community

• A community is a group of different populations interacting in a shared environment.
• Community interactions involve interactions between different species, such as predator-prey relationships.

Ecosystem

• An ecosystem encompasses all organisms and nonliving factors in a specific area.
• Ecosystems are characterized by interactions between biotic and abiotic elements.

Landscape

• A landscape is a group of ecosystems that may or may not interact.

Biome

• A biome encompasses ecosystems with similar climates and dominant communities.
• Classification based on predominant vegetation types.

Biosphere

• The biosphere encompasses all biomes and ecosystems, interacting within the planet's physical environment.

Biosphere

• The biosphere contains all ecosystems on the planet and includes land, water, and atmosphere.

This quiz covers the fundamental concepts of ecology, including the relationships between living organisms and their environment. It highlights the impact of human population growth on ecological systems and the importance of ecology for our survival. Test your understanding of key ecological principles and their relevance to human civilization.